Silicone is a synthetic polymer and is produced by a crosslinked polymer reinforced with silica. Further cross-linking takes place by heating with a particular catalyst (i.e. peroxide), to produce the required properties. Silicone has good environmental resistance to heat, cold, ozone, UV, humidity and abrasion. It has outstanding heat resistance, to over 230°C. Electrical resistance is also excellent, and Silicone is frequently used in high voltage/high current applications. However, Silicone can be modified with additives to make it electrically conductive. Silicone does not support microbiological growth, which makes it very useful in pharmaceutical and medical environments. Silicone is a high performance polymer and necessarily more expensive because of its properties. It is made in lower quantities and requires expensive equipment for the compound and the final product’s manufacture. Silicone is highly permeable to gas, which can be a useful property. Silicone is not classed as hazardous waste, and therefore can be disposed of according to local regulations.